#include<iostream>
#include<vector>
#include<algorithm>
#include<cmath>
#include<string>
#include<iomanip>
#include<numeric>
#include<queue>
#include<deque>
#include<stack>
#include<set>
#include<map>
#include<random>
using namespace std;
typedef long long ll;
const int mod=998244353;
int main(){
	static int n,k,a[100000];
	cin>>n>>k;
	for(int i=0;i<n;i++)
		cin>>a[i];
	int sum=accumulate(a,a+n,0);
	ll ans=0;
	for(int i=0;i<n;i++)
		ans=(ans*k+a[i])%sum;
	cout<<ans<<endl;
}